Method of making molded bodies of granular ob comminuted material



. c. L. NORTON. I METHOD OF MAKING MOLDED BODIES 0F GRANULAR 0RCOMMINUTED MATERIAL.

APPLICATION FILED AUG.29 I918.

Patented Mar. 2, 1920.

3 SHEETSSHEET I.

C. L. NORTON. METHOD OF MAKING MOLDED BODIES OF GRANULAR 0R commmunnMATERIAL.

APPLICATION FILED AUG.29. ISIS.

332,676. I Patented Mar. 2, 1920.

s SHEETS-SHEET 2.

I 1 .Jnveniav;

CharZedliYorZon/ t5 7 y fiMW/M C. L. NORTON.

METHOD OF MAKING MOLDED BODIES 0F GRANULAR 0R COMMINUTED MATERIAL.

APPLICATION FILED AuG.29. ma.

1,332,676; Patented Mar. 2, 1920.

3 SHEETS-SHEET 3.

Inven%0 Cfiarlea'llfforion dfiiorngys UNITED STATES PATENT OFFICE.

CHARLES L. NORTON, OF BOSTON, MASSACHUSETTS.

METHOD OF MAKING MOLDED BODIES 0F GRANULAR OR COMMINUTED MATERIAL.

Specification of Letters Patent.

Application filed August 29, 1918. Serial No. 251,872.

To all whom it may concern:

Be it known that I, CHARLES LADD NOR- TON, a citizen of the UnitedStates of America, and resident of Boston, in the county of Suffolk andState of Massachusetts, have invented new and useful Improvements inMethods of Making Molded Bodies of Granular or Comminuted Material, ofwhich the following is a specification.

My invention relates to the manufacture of brick shapes and similarbodies of assembled granules or particles which, individually, arerigid, non-plastic, irregular, so that they are hardly susceptible ofmutual mobility when in contact with each other, and therefore resistpressure applied with intent to cause an aggregate of such granules tofill and assume the shape of a mold. A conspicuous example of suchmaterial is the granulated ganister rock of which refractory silicabrick is made. This is granulated to a fineness which varies from i inchdownward, is gritty, the granules being hardly if at all capable ofslipping movement one over the other, when in close contact.

For purposes of molding into bricks, granulated ganister is mixed withwater and lime, the latter in about 2 per cent. proportion to theganister. While a liberal admixture of some lubricant material mightsupply the degree of internal fluidity or plasticity of the mass, itsincorporation therein in considerableproportion would seriously degradethe refractory character of the finished product.

So far as I am informed, attempts to force this silica-brickmaterialinto molds under pressure, have failed to produce the desired andindispensable filling of the corners and edges of the mold, doubtlessbecause the granular, gritty ganister resists plasticmovement the morestubbornly with the at tempt to coerce it into movement. Heretofore, thedamp coarse sand composed oi: ground ganister with its permissiblecontent of water and lime, has been introduced into metal molds by hand,introduced into the corners and edges as completely and densely as theconditions of operation permitted, smoothed oil with a trowel or similarimplement, then removed from the molds, dried, and eventually burnt inkilns.

The limitations imposed by the material and the heretofore employedmolding practice have resulted in defects, endured because unavoidableunder the circumstances, in the brick product. The corners and edges ofthe shapes are inferior in density and frequently imperfect in form;hardly any two bricks are of the same average density throughout; inburning, the bricks shrink unevenly, and corner and edge outlines arelost, both before and after firing.

The object of my invention is to introduce such diflicult material asgranulated ganister, into a brick-mold under such conditions ofdistribution, velocity and direction of movement, and quantity, that thecorners and edges of the mold will be completely filled, the density ofthe brick shape at corners and edges be such as to preserve shape, andpreferably be superior to the density of the molded shape at itsinterior regions; and so that all the brick-shapes produced will possessuniform average density.

The problem presented by these conditions is, primarily, to produce sucha condition Patented Mar. 2, 1920.

of mutual mobility in the gritty particles at the instant ofintroduction into a mold that they will not so impede each othersmovements as to prevent complete filling of the molds in the corners andedges; secondly, to succeed or supplement this momentary condition ofmutual fluidity by an intimate aggregation of the'particles themselvesand thus produce a generally uniform density and firmness in theinterior of theresulting mass.

I proffer, by my invention now to be described, a solutionof thisproblem in both its primary and secondary aspects, and also in sundrysubordinate but practically important other aspects, which will beelucidated in the course of description. I describe my inventions, forpurposes of full illustration and example, in their a plication to themanufacture of silica brie r, since the materials of which this productis composed pre sent in eminent-degree the obstacles which it is theobject of my inventions to overcome.

The method which is the subject of claim herein may doubtless bepractised by the aid herewith in the United States Patent Oflice.

In the drawings annexed to this specification which illustrate a machineadapted to my invention, in its structure and principles of operation,-

Figure 1 represents portions of a brick making machine, in. sideelevation,

Fig. 2, the same in end elevation and part in section, viewed at itsbrick-shape delivering end, the section taken at the line 22 g- Fig. 3,a plan view, partly in section on the line 3 3 (Fig. l)

Fig. i, the apparatus for delivering mate rial to the brick molds, inside elevation;

Fig. 5, the material-delivering apparatus, inend elevation;

Fig. 6, a detail, showing a brick-n1old in vertical longitudinalsection;

Fig. 7, a detail, showing; a brick-mold, in section at the line 7--7(Fig. 6)

Fig; 8, part of the troweling or leveling mechanism, in plan view;

Fig. 9, part of the same in side elevation;

Fig. 10, part of one of the side-rails oil the troweling or levelingmechanism in side elevation Fig. 11, part of said side-rail, in verticalcross-section;

Fig. 12, a detail, showing the feedinghopper, in side elevation;

Fig. 13, a sectional view of the said feedhopper;

Fig. 1d, perspective view of a pallet for receiving the molded brickshapes; and

Fig. 15, a perspective view of the pallet feeding mechanism.

The principal parts of the machine illustrated in the drawings are: Themold conveyer, comprehensively designated by the letter A; the pallet:l'eeder F; the pallet holder B; the pallet support C; which may beeither stationary or movable; the material feeder D; the troweling andleveling in struin'ent E; and the mold discharger G. The moving partsare actuated by a driving mechanism so that their several and relatedmovements are properly codrdinated to pro duce the successiveoperations.

The function of the mold conveyer A is to carry a succession ofbrick-molds M in continous cycle or repetition to and through thestations or regions in the machine where are performed the followingoperations. (1) Filling the mold, in all its parts and especially in itscornerportions, with a densely compacted mass of brick-material; (2)removing surplus material from over the mold and smoothing the surfaceof the material; (3) covering the mold with a plate or pallet; (4:)inverting; the mold so that the pallet becomes a support for the moldedbrick shape; (5') extruding the brick shape from the mold, (orwithdrawing the mold from around the shape) leaving the latter restingon the pallet.

The first operation of filling the mold takes place when the mold ispassing under the material-feeder D. This part of the machine comprisesmeans for intermittently releasing charges of brick-material at such aheight above the mold that, in falling to the mold, the granular orcomminuted material has an opportunity to become loosened ordisintegrated before it reaches the mold which is at the time inposition to receive it. Thus the material, instead of arriving at themold in compacted condition, is in open formation, constituting a heavyshower of granules which are separated from each other, albeit slightly,by intervening air. Within limits, therefore, the granules are mobilewith relation to each other. Those which strike the surfaces of the moldpercussively in advance of the general multi tude respond to the impactthus produced and would fly explosively in all directions, were it notfor the immediately succeeding arrival of the main body of the shower,which offers a cumulative obstacle to the rebound of the earlierarrivals. The only direction in which the first-arriving granules canmove without hindrance from their successors is toward the corners,edges and sides of the mold, and those granules which are in the van ofattack are driven by the discrete mass that follows them, into thecorner and edge recesses of the mold, while the condition of mutualseparation of granules persists and confers mobility on these granulesfirst to arrive.

Repeated experiments with a machine such as illustrated herein show,that if the nurse oli granulated material be packed in the hopper andthen suddenly released, so that it falls substantially as one piece, theresults are quite unsatisfactory, the brickinolds failing to fill at thecorners. Also, repeated experiments have shown that dribbling or sittingthe charge of granular material, so as to pij'otract the time ofdelivery of a full charge, and sepz'trate the granules relatively verywidely, both in space and time of arrival at the mold, defeats theobject and fails to fill the molds properly, especially at the corners.

Exactly what the practical limits of dis persion oil the granules mustbe, to effect the result arrived at, cannot be stated. The charge whenproperly delivered. is a shower, but a very dense shower, of granules.The effect is slight dispersion of granules at the instant of arrival atthe mold. followed almost instantly by a consolidation of the multitudeof granules, with emphatic impact.

The mutual mobility of granules progressively decreasesas the mold-isfilled, the

main body of falling granules furnishes the force and the supply ofmaterial necessary to hold in place those that have lodged in thecorners and edges of the moldcavity, and to render the entiremold-charge compact and dense. The granules which, arriving first at themold, are projected into the corner and edge portions of the mold athigh velocity, due to their own rate of fall and also to increments ofvelocity acquired by impact from successively arriving granules, arecompacted together more densely than granules in the interior of themolded shape, which fall into place more as a mass than do those whichpenetrate to the corners and edges. In order to insure complete andsubstantially homogeneous interior density to the molded shape which iseventually to be extruded from the mold, each charge of material ispreferably a quantity decidedly in excess of that required to fill theintended volume of the finished brick shape at least and preferably ofthe order of to 75% excess. The surplus of material over the quantityrequired to just fill the mold, acts by impact to tamp the contents ofthe mold into final compact condition, leaving the uncompacted topportion well above the plane of the top of the mold. The surplus liesover the mold, to be removed by subsequent operations.

The succession of events in the filling of the mold, above described.takes place in a fraction of a second. The height, and

' therefore time of fall of each charge of material from the point ofits liberation to the mold may be varied, but should be sufficient toallow the mass of granules to separate, to become comparativelydiscrete. before striking the mold, in order that the characteristicmutual mobility of the granules first to reach the mold may be produced.For the manufacture of nine inch straight silica bricks, a drop oftwelve feet has been found in practice to give satisfactory results, thematerial being crushed ganister, with 2 per cent. of lime and betweennine and eleven per cent. of water, approximately. In order to preventretardation of granules by contact with the sides of the chute throughwhich they fall, from affecting the velocity of the granules which fallinto the mold nearest its sides, the chute-as shown in the drawings-ismade somewhat larger in horizontal section than the mold. Thus onlyfreely falling granules enter the mold.

Experience has shown that the most important part of the chute is thatwhich is immediately over the mold. The sides of the chute at its lowerend confine the n'iass of granules and prevent lateral dispersion. Theside of the. chute under which the mold passes after being filled shouldafford clearance, so that as the surplus material is scraped off by thelower edge of the chute on that side there will still remain a smallsurplus above the plane of the top of the mold.

Whatever may be the specific mode of producing a discrete yet closelyassembled aggregate of granules, and projecting them into a mold, theresult characteristic of my invention will be produced if the abovedescribed physical condition and principle of operation be present,viz., initial impact, upon and in a mold, of separated and mobilegranules, followed by rapidly cumulative impact ofother granules uponthe earlier to arrive, and the continuation of such cumulative impact ofgranules until the entire mold space is filled, and compacted by surplusmaterial acting to tamp the mold contents.

The effect of rebound of hard, non-plastic granules against similargranules which follow closely after them is to drive the first granulesto arrive at the mold surfaces laterally into the corners and edges. Asthe mold fills, this lateral, quasiexplosive propulsion of granules,each of which is pursued by its successors, builds up a layer at thesides of the mold, which is denser than interior portions of the finallyproduced brick-shapes for the reason that the rebound of a pan ticlefrom the immovable mold surface is more emphatic, and the return impactfrom successive granules more forcible, than at regions in the interiorof the brick shape.

In the operation of the machine herein described, each mold, M, in thechain receives its charge as it travels beneath the material-feeder D,and then proceeds to the troweling' and leveling instrument E. Theinteriorof the chute D is somewhat larger in horizontal cross-sectionthan the mold M, so only those granules of which the fall is unimpededby contact with the sides of the chute will enter the mold. Here thesurplus material is scraped off the mold, and the remaining mold-contentsmoothed and compacted at its upper surface. Then, by operation of thepallet feeder F and pallet holder B a flat metal plate, called a pallet,is placed and held as a cover over the full mold, and as the moldcarrier A continues to move the mold along it inverts it, so that thepallet becomes the bottom of the mold, supporting the molded shape. Inthis condition the mold and pallet arrive at the pallet support C. As

the mold and pallet progress, each on its own carrier, their respectivepaths of movement gradually diverge, and by means of a mold dischargingdevice G (presently to be described more in detail) the molded shape isextruded, the mold drawn from it, until, at the delivering end of thepallet carrier the pallet, with the brick-shape resting on it emergesfrom the machine, to be removed by any suitable means and taken to thedrying chambers. When the pallet support C is stationary it is made assmooth as possible so that the pallets may be caused to slide freelyalong by the ad vancing molds.

The molds may be single or multiple, as desired; the mold shown by wayof illustration has six compartn'ients, each adapted to :Eorm the shapeof a straight rectangular brick.

The following; detailed description of the several members of the briclrmachine will enable any person skilled in the mechanical arts to erectand operate such a machine.

Referring to Figs. 1, 2 and 3: The moldconveying member of the machineshown in the drawing consists oi? sprocket wheels A? and A and thesprocket chain A The molds M are joined at intervals to links of thechain A these links being provided at their joints with rolls M Theserolls after leaving the sprocket wheel A? are sustained by and travel onthe rail F which is secured to the frame of the mar chine.

Each mold is made in two parts as shown in Figs. 6 and 7. The box part Mis a cellular frame divided into rectangular compartments by thepartitions M The bottom part M comprises a number of platforms 1/ whichconstitute the bottoms of the mold compartments, lying between thepartitions M The bottom part M is mounted in sliding relation to the boxpart M the sliding traverse being); detern'iined, guided and limited bythe slots M formed in the ends of the box part of the mold in whichslide the roll studs M which are se cured to the bottom part of themold. This bottom part is cut away or slotted at M to accommodate themold partitions M when. the bottom part is mo ed, as hereinafterdescribed, to extrude shapes of molded material from between the moldpartitions M Returning to Figs. 1 and 2; at one stage of their movementwith the sprocket chain A the molds M pass over the supporting beam at Fso that the bottom part M of each mold at that point of its travelderives a. reinforced support from. the beam F It is at this point thatthe material to be charged into the mold compartments strikes the moldforcibly in a manner herein described and at that point therefore themold bottom is preferably given the rigid and adequate support of thebeam F Those members of the machine which are representative of themold-charging factor which is part oi. my invention, are not shown inFigs. 1, i2 and 8 but are illustrated in Figs. 4 and 5 and in furtherdetail in Figs. and 13. Referring to these figures; directly over thesupporting beam F the material-feeding and charging factors arearranged; these comprise a vertical, hollow,

tubular chute D a he J is]? D immediatcl' l l over the chute andintermittently operating hopper gates D The material, as for in stanceground ganister with a small content of lime and proper proportion ofwater, is supplied to the hopper D in any desired manner. Supplyingmechanism is not shown in thes. drawings since any suitably designedbucket conveying apparatus would serve the purpose. It being understoodthat at proper intervals the hopper D is given a supply of material, theintermittent material-feeding mechanism will operate to release asuitable measured. charge of material from the hopper. Thecharge-releasin qnicclnmism (see I igs. 152 and 13) con sists of a pairoi? swinging gates D mounted upon the swinging arms D. At or near theends of these arms are mounted bosses D; the arms are extended abovetheir pivot D and carry counter weights D. A sprocket chain 1, drivenfrom the shaft which carries the sprocket chain A turns the shaft 1 uponwhich arms I are mounted, each of these arms carr' a cam plate I and acounterweight is the shaft I rotates it periodically carries the cam 1*between the bosses 1) moving; them apart and thus opening the hoppergates D and discharging: the load of material in the hopper from whichit then falls freely through the chute D The intermittent release ofmaterial :irosn the hopper D is so timed that when the r-iaterialreaches the bottom of the chute D there is presented to it one of theopen molds l The quantity oi material. intermittently discha L .d fromthe hopper D should be in material excess of that which is needed totill the compartments of the mold M leaving surplus on top of the moldto be manipulated by subsequent op erations oil the machine. Ashereinbefore explained, the phy cal condition of the material. thespacial lations of its particles are such that when the charge ofmaterial strikes the mold its particles fill all oi the corner and edgeparts of the mold compartiuents in a condition oi? high density,

and its general interior mass is compactly and uni'Formly distributedthrough the mold spaces. It at this point in the operation of themachine that the supporting beam F provides the desirable rigid supportfor the mold and relieves other parts of the mecha nism cm the full dutyoi? sustaining the impact of the ch arge oi material.

Each mold after being thus charged travels onward in the machine, thelower edge oi? the chute scraping off much of the excess material. andthe material remaining in excess on the top of the mold is first subjected to a supplemental smoothing and compacting pressure by the idleroll H. Thence each mold passes under the scraping and trowelingapparatus, generally designated as E in Figs. 1, 2, and 3, and shownmore in detail in Figs. 8, 9, 10, and 11. This scraping and trowelingmechanism consists of a frame of which the principal members are theside rails E These side rails are pendulously suspended from the frameof the machine by means of thin metal straps E of which there is one oneach corner of the frame. This flexible mode of suspension provides fora vibratory movement of the frame back and forth across the machine.This vibratory movement need have no special time relation with theother parts of the machine. It might indeed be vibrated by hand, butpreferably of course, any of the obvious mechanical expedients forimparting such vibratory motion from the driving mechanism of themachine should be adopted.

The means for vibrating the frame E chosen for the purpose ofillustration comprises a shaft S journaled on the frame at s, s and sand connected to one of the power shafts through bevel gears S, theshaft S being offset at S to form a crank which is connected with theframe E by a connecting link S The shaft S is so positioned that thelink S is in alinement with the path of reciprocation of the frame E andthe shaft is geared to the source of power so as to vibrate the framefairly rapidly.

The scraping and troweling members mounted on the frame E consist ofbars E adjustably secured at their ends to the side rails E andpreferably extending across the machine at an angle. The shapes of theoperatin surfaces of these bars may vary; they s ould be of suchcharacter as best to remove and smooth down progressively the materialin the molds M so as finally to leave the molds filled level to the top.I find that smoothing and troweling plates, such as E secured to thelast of these leveling and smoothing bars to operate on the materialprovide a desirable finishing effect. Such flexible plates are indicatedat E Figs. 3, 8 and 11.

From the troweling and finishing plates E, the molds M are carried bythe chains A to and over the sprocket wheels A and in passing aroundthis sprocket wheel the molds are inverted. In order to keep the moldedmaterial from spilling at this stage in their travel the molds arecovered with pallets P. These pallets, one of which is shown in detailin Fig. 14, consists of plates with, an upturned edge along one side.This upturned edge engages with the edge of the mold M which in itsreturn travel from the wheel A to the wheel A is the leading edge.Adjacent to the sprocket wheel A there is mounted the pallet holdingbelt B which runs over the drums B B and B The belt B is yieldinglytensioned by slidably mounting the journal bearing 13* of the pillley Bin a vertical guideway B -and suspending adjustable weight B on thejournal bearing 13. The pallets, which may be introduced by hand andplaced upon the molds M as these travel in succession on the sprocketwheel A are nipped between the belt B (which is kept under tension) andthe molds M, and thus held in place to prevent the material in the moldsfrom spilling out or from leaving the molds until the proper timearrives for extrusion of the molded shapes from the molds themselves.

For the purpose of illustration I have shown an automatic pallet-feedingdevice F in Figs. 1 and 15, this device comprising an inclined slidewayF extending into the space between the mold carrier and the belt B and adog F adapted to engage the upturned edge of the lowermost pallet andserve as a stop. The dog F is mounted on a spring F so as to swinglaterally and disengage the lowermost pallet. A cam F is provided on thedog so as to be engaged by the molds M to free a pallet for each mold asit passes.

As the chain A caries the molds thus inverted toward the sprocket wheelA the pallets P are drawn from the pallet holding belt 13 across the gapbetween the drums B and C so that the carrying belt C thereaftersupports the pallets. This carrier belt C which is mounted on the drumsC and C is driven by means of a sprocket chain C at the same speed asthe sprocket chain A. The rolls M now rest and travel upon the inclinedrail F so that the box part M of each mold in its travel from the drum 0to the sprocket wheel A is moved away from the carrier belt 0 a distanceabout equal to the depth of the material-filled compartments of themold. Above the sprocket chain A and on each side thereof a rail G issecured to the frame of the machine, this rail being parallel with thepallet-supporting part of the carrying belt C. The rollstuds M which aresecured to the bottom part of each mold M engage the lower edges ofthese rails G and as the rails F and rails G are mounted at an angle onewith the other the paths of movement of the rollstuds M and roll-studs Mconverge, and thus the bottom parts M of the molds M are moved withrelation to the box parts M so as progressively and gently to extrudethe molded shapes from the molds themselves, finally freeing them andleaving them resting on the pallets P to be carried out of the machineupon the carrying-belt C. As the pallets, each with its load of moldedshapes, emerge they are removed to be taken to the drying-house wherethe molded shapes go through their reliminary drying treatment.

I claim:

The method of making silica brick, or the like, Which comprisesprojecting, as by drop ping, aquantity of non-plusticl granules,like

5 ground ganister, to a mold, said quantity being substantially greaterthan the capacity of the mold, in such manner that the gram ules Willsepa ate slightly in transit to the mold so as to constitute a closelyassembled but discrete aggregate on arrival at the 10 mold.

Signed by me at Boston, Massachusetts, this ninth day of August, 1918.

CHARLES L. NORTON.

